feat: OpenAI-compatible /v1/chat/completions endpoint (drop-in for OpenRouter)

server.js

@@ -201,4 +201,111 @@ app.post('/api/chat', express.json({ limit: '50mb' }), async (req, res) => {
     }
 });
 
+// ══════════════════════════════════════════════════════════════
+//   OPENAI-COMPATIBLE ENDPOINT  (/v1/chat/completions)
+//   Drop-in replacement for OpenRouter. Map ext/ or any OpenAI
+//   client here and it'll route through our Claude Max account.
+// ══════════════════════════════════════════════════════════════
+
+const CC_SYSTEM_PREFIX = "You are Claude Code, Anthropic's official CLI for Claude.";
+
+function mapModel(name) {
+    if (!name) return MODELS.sonnet;
+    const n = String(name).toLowerCase();
+    if (n.includes('haiku')) return MODELS.haiku;
+    if (n.includes('sonnet')) return MODELS.sonnet;
+    if (MODELS[n]) return MODELS[n];
+    return MODELS.sonnet;
+}
+
+function translateContent(content) {
+    if (typeof content === 'string') return content;
+    if (!Array.isArray(content)) return String(content ?? '');
+    return content.map(b => {
+        if (!b || typeof b !== 'object') return { type: 'text', text: String(b ?? '') };
+        if (b.type === 'text') return { type: 'text', text: b.text || '' };
+        if (b.type === 'image_url') {
+            const url = b.image_url?.url || '';
+            const m = url.match(/^data:([^;]+);base64,(.+)$/);
+            if (m) return { type: 'image', source: { type: 'base64', media_type: m[1], data: m[2] } };
+            return { type: 'text', text: '[image: remote URL, not supported]' };
+        }
+        if (b.type === 'image' && b.source) return b;
+        return { type: 'text', text: JSON.stringify(b).slice(0, 200) };
+    });
+}
+
+app.post('/v1/chat/completions', express.json({ limit: '50mb' }), async (req, res) => {
+    const { model, messages = [], max_tokens = 4096 } = req.body || {};
+
+    const systemParts = [CC_SYSTEM_PREFIX];
+    const anthMessages = [];
+    for (const m of messages) {
+        if (!m || !m.role) continue;
+        if (m.role === 'system') {
+            const s = typeof m.content === 'string' ? m.content : JSON.stringify(m.content);
+            if (s && s.trim()) systemParts.push(s.trim());
+        } else if (m.role === 'user' || m.role === 'assistant') {
+            anthMessages.push({ role: m.role, content: translateContent(m.content) });
+        }
+    }
+    if (anthMessages.length === 0) return res.status(400).json({ error: { message: 'messages required' } });
+
+    const accessToken = await ensureFreshToken();
+    if (!accessToken) return res.status(500).json({ error: { message: 'no credentials' } });
+
+    const modelId = mapModel(model);
+
+    try {
+        const upstream = await fetch('https://api.anthropic.com/v1/messages', {
+            method: 'POST',
+            dispatcher: anthropicAgent,
+            headers: {
+                'Content-Type': 'application/json',
+                'Authorization': `Bearer ${accessToken}`,
+                'anthropic-version': '2023-06-01',
+                'anthropic-beta': 'claude-code-20250219,oauth-2025-04-20,interleaved-thinking-2025-05-14,fine-grained-tool-streaming-2025-05-14',
+                'x-app': 'cli',
+                'User-Agent': 'claude-cli/2.1.114',
+            },
+            body: JSON.stringify({
+                model: modelId,
+                max_tokens,
+                stream: false,
+                system: systemParts.join('\n\n'),
+                messages: anthMessages,
+            }),
+        });
+
+        if (!upstream.ok) {
+            const err = await upstream.text();
+            return res.status(upstream.status).json({
+                error: { message: err.slice(0, 800), type: 'upstream_error', code: upstream.status },
+            });
+        }
+
+        const data = await upstream.json();
+        const text = (data.content || []).filter(b => b.type === 'text').map(b => b.text).join('');
+
+        res.json({
+            id: data.id || ('chatcmpl-' + Date.now()),
+            object: 'chat.completion',
+            created: Math.floor(Date.now() / 1000),
+            model: model || modelId,
+            choices: [{
+                index: 0,
+                message: { role: 'assistant', content: text },
+                finish_reason: data.stop_reason === 'end_turn' ? 'stop' : (data.stop_reason || 'stop'),
+            }],
+            usage: {
+                prompt_tokens: data.usage?.input_tokens || 0,
+                completion_tokens: data.usage?.output_tokens || 0,
+                total_tokens: (data.usage?.input_tokens || 0) + (data.usage?.output_tokens || 0),
+            },
+        });
+    } catch (e) {
+        res.status(500).json({ error: { message: e.message, type: 'proxy_error' } });
+    }
+});
+
 app.listen(8108, () => console.log('sechenov :8108'));